1. Field of the Invention
The present invention relates to a truck structure of a skateboard and, more particularly, to a structure on which a truck is detachably and attachably mounted.
2. Description of the Related Art
Heretofore, as one example of the truck structure of the skateboard, a truck structure has been known. It changes a rudder angle of a wheel W leftward and rightward corresponding to a deflection of the truck, as shown in FIG. 7.
In such a truck structure 30, a top face of a truck bearer portion 31 which journals the wheel W is formed in the disk-shape, and contacts a disc shaped-bottom face of a weighting table base portion 32 fixed to a deck D, and is pivotally connected to P at a central position.
Further, the weighting table base portion 32 is connected to a box portion 33 which stores a coil spring S, and an elastic force of the coil spring S can be adjusted by an adjustment bolt 35 which penetrates a hollow of the coil spring S.
Further, the top face of the truck bearer portion 31 is provided with a protrusion portion 36, on the upper part of which is provided a protrusion axis 37, and the protrusion portion 36 is engaged with a long hole 38 formed almost in the shape of a fan on the top face of the weighting table base portion 32, and is allowed to slide within the range of the long hole 38.
A base end of a link piece 39 which penetrates the adjustment bolt 35 within the box portion 33 and is pivotally connected thereto and pushingly abuts against a top end side of the coil spring S, is pivotally connected to the protrusion axis 37.
The protrusion axis 37 placed in a neutral position is arranged on the axis line of the adjustment bolt 35. When a force works to make turns leftward and rightward, both the protrusion portion 36 and the protrusion axis 37 turn leftward and rightward within a constant range, and gradually move away from the axis line of the adjustment bolt 35. Therefore, accompanied with this movement, the link piece 39 is pulled and compresses the coil spring S to make it repulsive.
When no force is applied leftward and rightward on the truck, the wheel W is returned to the neutral position through the link piece 39 by an elastic resettability of the coil spring S.
Hence, a conventional structure is integrally provided with a truck and a mechanism which allows the truck to turn leftward and rightward and, therefore, a modification or a replacement of a truck portion is not easily performed and there has been a problem in that a maintenance, a tuning, or the replacement and the like of the truck are hard to perform.
Further, a pivotal stroke of the link piece 39 is regulated by the long hole 38 formed at the top face of the weighting table base portion 32, and the protrusion axis 37 is required to be provided on the protrusion portion 36 and, thus, the structure has been made complicated. In addition, the crossing of the axis lines at both ends of the link piece 39 imposes a torsional load to the link piece 39, and this has necessitated a sufficient strength to be given to the link piece 39.
Moreover, since the turning of the truck bearer 31 for the weighting table base portion 32 concentrates a stress onto the pivot P, it tends to be fatigued and a problem may occur in its durability.